The role of closed-loop attitude dynamics in adaptive UAV position control

This paper presents the design and the stability analysis of an adaptive position controller for Unmanned Aerial Vehicles (UAVs). Considering a hierarchical control scheme, the novelty of this work is the definition of a systematic approach to design a position controller based on Model Reference Adaptive Control (MRAC) theory taking into account not-fast closed-loop attitude dynamics. After having reformulated the problem considering the attitude dynamics as pseudo-actuator, the authors exploit an existing Linear Matrix Inequality (LMI) based hedging framework designed such that the adaptation performance is not affected by the presence of actuator dynamics. Results from simulations and from experiments on a platform designed to replicate the longitudinal motion of quadrotors are provided to illustrate the performance of the proposed control scheme

Endogenous Sanctioning Institutions and Migration Patterns: Experimental Evidence

We experimentally analyze the effect of the endogenous choice of sanctioning institutions on cooperation and migration patterns across societies. In our experiment, subjects are allocated to one of two groups, are endowed with group-specific preferences,and play a public goods game for 30 periods. Each period, subjects can move between groups and, at fixed intervals, can vote on whether to implement formal (centralized) sanctioning institutions in their group. We compare this environment to one in which only one group is exogenously endowed with sanctioning institutions. We find that subjects' ability to vote on institutions leads to (i) a more efficient partition of subjects between groups, (ii) a lower migration rate, (iii) an increase in overall payoffs, and (iv) a decrease in both inter- and intra-groups (payoff) inequality. Over time, subjects tend to vote for sanctioning institutions and contribute to the public good

Leonardo Drone Contest Autonomous Drone Competition: Overview, Results, and Lessons Learned from Politecnico di Milano Team

In this paper, the Politecnico di Milano solutions proposed for the Leonardo Drone Contest (LDC) are presented. The Leonardo Drone Contest is an annual autonomous drone competition among universities, which has already seen the conclusion of its second edition. In each edition, the participating teams were asked to design and build an autonomous multicopter, capable of accomplishing complex tasks in an indoor urban-like environment. To reach this goal, the designed systems should be capable of navigating in a Global Navigation Satellite System (GNSS)-denied environment with autonomous decision making, online planning and collision avoidance capabilities. In this light, the authors describe the first two editions of the competition, i.e., their rules, objectives and overview of the proposed solutions. While the first edition is presented as relevant for the experience and takeaways acquired from it, the second edition solution is analyzed in detail, providing both the simulation and experimental results obtained

How Merchant Towns Shaped Parliaments: From the Norman Conquest of England to the Great Reform Act

This is the final version. Available from the American Economic Association via the DOI in this recordWe study the emergence of urban self-governance in the late medieval period. We focus on England after the Norman Conquest of 1066, building a novel comprehensive dataset of 554 medieval towns. During the Commercial Revolution (twelfth to thirteenth centuries), many merchant towns obtained Farm Grants: the right of self-governed tax collection and law enforcement. Self-governance, in turn, was a stepping stone for parliamentary representation: Farm Grant towns were much more likely to be summoned directly to the medieval English Parliament than otherwise similar towns. We also show that self-governed towns strengthened the role of Parliament and shaped national institutions over the subsequent centuries

Anticipated Discrimination, Choices, and Performance: Experimental Evidence

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.This paper studies experimentally whether potential perceived discrimination affects decisions in a labor-market setting with different stereotypes. Participants are assigned to a seven-person group and randomly allocated a role as a firm or worker. In each group, there are five workers and two firms. The only information firms have about each worker is a self-selected avatar (male, female or neutral) representing a worker's gender. Each firm then decides which worker to hire. Female workers react to potential discrimination when they know the task is math-related, but not otherwise. Men choose similar avatar patterns regardless of the task. Men do perform at much higher levels in the math-related task, but there is no difference in performance in the emotion-recognition task, where there is a strong female stereotype.American University of SharjahUniversity of Exete

Smoother-Based Iterative Learning Control for UAV Trajectory Tracking

This letter presents a data-based control approach to achieve high-performance trajectory tracking with Unmanned Aerial Vehicles (UAVs). We revisit an existing Iterative Learning Control (ILC) algorithm based on the notion that the performance of a system that executes the same task multiple times can be improved by learning from previous executions. While we will specifically refer to multirotor platforms for the experimental validation, the formulation can be applied to any dynamic system (including systems with underlying feedback loops). The novelty of this work is the introduction of a smoother to estimate the repetitive disturbance to improve the learning performance. This estimator must rely on an accurate system model that has been obtained through a black-box identification procedure using the Predictor-Based Subspace Identification (PBSID) algorithm. A Monte Carlo analysis has been carried out with the aim of showing the performance improvements and limitations of the proposed algorithm with respect to existing approaches. Finally, the proposed approach has been validated through experimental activities involving a small quadrotor performing an aggressive manoeuver

Sovereign bail‐outs and fiscal rules in a banking union

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record This paper studies optimal fiscal rules in a two-country economy in which cross-country linkages between sovereign debts and banking sectors motivate bail-outs among countries. The first-best sovereign borrowing, which is contingent on countries' output gap, cannot be achieved in the presence of asymmetric information on a country's potential output. Because bail-out induces overborrowing, fiscal rules can be implemented to prevent the ensuing inefficiency. A mechanism can be designed to induce a country with low potential output (i.e., a small negative output gap) to run an optimal budget deficit upon receiving a (ex-post) transfer from the other country. We characterize conditions under which this fiscal mechanism Pareto dominates a `cyclically-adjusted' fiscal rule imposing a unique ceiling on a country's borrowing, independently of its potential output. We apply our setting to discuss implications for fiscal rules within the European Monetary Union